Diabetes can cause a number of serious side effects including eye conditions like cataracts and diabetic retinopathy, a condition that causes progressive damage to the eyes. Researchers are finding ways to see the very early signs of diabetic eye damage, so they can treat it before the damage is done.

For years, 63-year-old Barbara Alpan relied on her daughter Lara for rides, but not anymore. She was diabetic in her thirties, and it eventually took a toll on her eyes.

Barbara told Ivanhoe, "If I was driving and somebody came up on the left, I wouldn't have seen them."

Rithwick Rajagopal, an ophthalmologist at Washington University School of Medicine in St. Louis, is an expert in diabetes-related vision loss.

Dr. Rajagopal said, "Currently, diabetic retinopathy is diagnosed and treated at the late stages of the disease."

For years, doctors have blamed vision loss on blood vessel damage around the retina, but new research shows eye injury may begin much earlier in nerve cells. Dr. Rajagopal and his colleagues fed mice a high-fat diet, giving them diabetes and then diabetic retinopathy. At six months, the mice showed signs of nerve problems.

Researchers did not see actual blood vessel damage in the mice until 12 months. Dr. Rajagopal said this finding could lead to earlier diagnosis.

"Eye tests for example that might be able to tell us this person is at high risk of developing diabetic retinopathy, while this other person might not be," Dr. Rajagopal told Ivanhoe.

That could lead to early treatments. Doctors say Barbara was an exception. Surgery restored her eyesight despite advanced disease.

Barbara's daughter, Lara said, "It's had a huge impact on her well-being."

Also on her confidence behind the wheel.

Researchers say other studies indicate people with diabetes go through a phase that seems to be similar to the early nerve damage that Washington University researchers found in mice. Doctors say it could be several years before new therapies could be developed to stop or reverse the nerve damage.